This invention relates to apparatus for and method of applying a lid to a filled box or case, and more particularly to apparatus for and method of lidding a case filled with a product, such as wrapped reams of paper, in which the lid is a so-called telescoping lid formed from a one-piece, preslotted blank with the lid being formed around the filled case.
In packaging wrapped reams of paper or the like, it is important that the reams be tightly packaged in the case with the reams uniformly supported on the bottom of the case and with the lid bearing directly on the topmost reams so that when several cases are stacked one on the other the weight of the cases is carried by the reams rather than by the sides of the case which could cause the case to partially collapse with possible consequent damage (i.e., bending) of the reams.
Generally, two types of boxes or cases are used to package wrapped reams, the first being a regular slotted container (RSC) having upper flaps which are folded down to close the case. The second type of case is an open top case which may be formed from either a half slotted container (HSC) similar to an RSC without the top flaps or from a so-called tray-type case formed from a preslotted one-piece flat blank. In the co-assigned U.S. Pat. No. 3,953,956, apparatus is disclosed which forms the fold lines for the top flaps at the same level as the height of the reams (even though the height of the reams may vary from case to case) and which folds down the top flaps thereby to insure that the reams support the weight of the other cases stacked thereon. Open top cases have been heretofore known to be well suited for packaging wrapped reams of paper because the height of the case can be selected so as to insure that with the desired number of reams placed in the case the reams extend above the upper edges of the case so that when a telescoping lid is fitted on the open top case the center panel of the lid will bear on the reams rather than on the upper edges of the case. Because the height of the reams in the case may vary from case to case, this height variance may be readily accommodated by the open case and the overfitting, telescoping lid.
It is known that by forming a telescoping lid from a flat blank around a case to be lidded a tighter package will result and dimensional variances of the case and of the product being packaged can be readily accommodated. Generally, these telescoping lids are formed from a preslotted and prescored flat blank of corrugated paperboard having a central panel and flaps at the sides and ends of the central panel which may be folded down on the sides and ends of the case. Either the side or end flaps of the lid (these flaps constituting major flaps) have outer end portions which are adapted to be folded perpendicular to their respective flaps in on the case and to be secured to the other or minor flaps, as by gluing, so as to form an overfitting lid. Typically, prior lidding apparatus involved fitting the case on an case, forming the lid around the elevator, compressing the lid in against the case immediately after forming the lid so as to bring the flaps into contact with previously applied adhesive, holding the lid under compression for a time sufficient to permit the adhesive to set, and then off-loading the case from the elevator. Also, the mechanisms of these prior lidding apparatus for folding down the flaps and for compressing the lid in on the case were relatively complicated.
Reference may be made to such U.S. Pat. Nos. 3,634,995 and 3,913,300 which discloses prior art lidding machines generally similar to the apparatus of the present invention.